(1) Until now, it has been common for people to try to select the well fitting shoe based on the foot size (length) and width. But the information on the size and width is not enough to select the well fitting shoe, because the individual feet have a variety of forms. Therefore, the new foot information format which represents foot shape feature has been desired instead of the foot size and width information.
(2) For the recent decades, the optical scanning system has been developed and used for three dimensional foot shape measurement. The scanned data is better in representing the complicated foot form than the traditional craftsmanship measurement data using the tape measure and the height gauge.
However, it has not been possible to identify which part of foot has to be compared as the correct position, or which position on the foot has to be the base point for the foot measurement in the case of comparison between or among the plural foot shapes. Thus, the quantitative comparison of three dimensional foot data has not been possible, even though the big/small judgment has been possible.
(3) And the data size of the scanned raw data is so large, that it makes network communication load heavy. Then the efficient and light data format has been desired to reduce the data size.
(4) There has been the FFD technique which is a technology to compare the three dimensional forms.    (T. W. Sederberg: Free Form Deformation of Solid Geometric Models, proceedings of ACM SINGGRAPH'86 in Computer & Graphics, 20–4, 151–160 (1986))
The following references relate to the FFD technique:                Japanese Patent Application Disclosure Hei10-240964 (Reference 1)        International Patent Application No. PCT/JP00/02297 (Reference 2)        
When this FFD technique is used for deformation/comparison of plural three dimensional form data, each three dimensional form data has to have the corresponding landmarks. For example, if there are two three dimensional forms data, they must have the landmarks, such as the rearmost point of heel and the tip of great toe, which have the same anatomical meaning in every foot.
The FFD technique can quantify the difference between the two forms by deforming the landmarks of one foot to become those of the other form.
Until now, the FFD technique has not been applied for deformation/comparison of plural foot forms, because this technique can not be used for the three dimensional form data without landmarks, even if they were distributed.
(5) Over and above, there are some unsuitable cases to determine the landmark position on the surface of the scanned foot data without landmarks. It is difficult to determine the correct position of the anatomical landmark on the fleshy and smooth foot surface. It is also difficult to determine the landmark position only from the three dimensional foot surface data, because the differences in the three dimensional morphology in the fleshy and thin foot are large.